Passenger propelled wheel chair



Jan! 30, 945. A. G. M. KELLEY 2,368 142 PASSENGER PROPELLED WHEEL CHAIR Filed Sept. 18, 1942 Patented Jan. 30, 1943 PASSENGER PROPELLED WHEEL CHAIR Alphonsus Gerard Ignatius 'Michael Kelley,

Horsham, Victoria, Australia Application September 18, 1942, Serial No. 458,798 In Australia September 30, 1941 8 Claims.

This invention relates to an improved passenger propelled wheel chair which has been specially devised in order to obviate disadvantages of known wheel chairs and to provide many advantages not available in the said known chairs.

The primary object of this invention is to provide a wheel chair which occupies relatively small space, which may be propelled by hand actuated mechanism without imposing severe physical strain on the user and which may be turned if desired, within its own length by special devices arranged to be actuated by control means that are operable by the feet or hands of the user.

Another object of this invention is to provide a wheel chair of the kind referred to, which will be compact and robust, easy to manipulate and relatively cheap to manufacture.

One important feature of this invention relates to steering devices which include cams fixed relatively to the rear wheels, means to connect the said cams so that they move in unison, and means to actuate one or other of the said cams to impart desired turning movement thereto by a direct pull through a connecting link or the like from actuating means such as pedals or the like.

A wheel chair according to this invention will not be liable to tip over however tight the lock to which th steering wheels are turned, all four wheels being arranged to travel around a common turning point, each following its own concentric track, and displaying no tendency to swing away from the centre of rotation.

Known wheel chairs have been fitted with caster wheels, and in such wheel chairs the tendency to overturn, when steered in a sharp curve has been an inherent defect.

A practical preferred embodiment of the invention is illustrated in the accompanying drawing, wherein Fig. 1 is a side elevation of the main parts of the wheel chair;

Fig. 2 is a plan view;

Fig. 3 is a plan View showing a modified construction;

Fig. 4 is a view showing the arrangement in Fig. 3 with the control cams and associated mech-' anism in full lock position;

Fig. 5 is a diagrammatic plan of a further modification of the arrangement shown in Fig. 2,

showing auxiliary cams below the transmission ard 3', and side members 4 extend back to rear uprights -5, forming in elfect side frames which are connected by a front transverse member 6 which forms a front seat support, and a rear transverse member 1 which supports the seat at the rear.

Each rear wheel 9 is supported in a fork ID at the lower end of a vertical stem l I rotatably upported in a bearing plate l2 carried by'a rear upright 5 of each side frame. Means such as a spring Ha. may be provided whereby each said stem is resiliently influenceddownwardly but may rise independently to absorb shock, the stem ll sliding telescopically in a tubular member 5a.

Steering means for each rear wheel 9 include a cam l3 fixed on each aid vertical stem I about the before mentioned fork to, and each said cam l3 has a peripheral track I4, in which is secured an end of a flexible member l5 such as a chain secured at l5b whereby the cams are connected to move in unison.

The means to control the steering may c'omprise a pair of pedals, each of which include a toe piece I6 and a heel support I'l. Connected to each toe piece I6 is an outer arm l8 and an inner arm I9, both pivotally connected to a rearward cross bolt 20, and a leeve 20a on the bolt carries a bellcrank lever having alshort outer arm 20band an upwardly extending inner arm ZOcQsaid An arm 25 (Figs. 3, 4) or cable 25a (Figs. 1, 2 6) is flexibly connected at 26 to the top of the lever 20c and the said arm or cable extends back to an articulated drag link 21 which is pivotally secured at 28 to a cam IS.

A stop 29 is provided on each cam I 3 forwardly of a line connecting the axes of the rear wheels, and at such position that as a cam swings rearwardly the stop 29 meets the articulated drag link 21 preventing the latter fouling the vertical stem 1 l and locating the said drag link so that it does not reach a dead centre position. The drag link is articulated so as to ensure the desired leverage to transmit movement in the opposite direction when a pedal is depressed.

It will be seen that as a cam swings forwardly the chain is constrained to travel around a curve of increasing circumference, and as the other cam swings in the same direction, the chain travels around that cam on a curve of decreasing circumference.

The principle of operations is as follows:

Presuming right hand pedal is depressed, the point X where the axial lines of the two rear wheels intersect will travel along the axial line of the front wheels, from infinity to a point midway of the front wheels, in a right hand direction (see Fig. 2). As the chain moves around the right hand cam on a curve of progressively increasing circumference, and pulls the chain around the other cam on a curve of progressively decreasing circumference, a differential movement of the rear wheels is obtained, and thus no matter how great or slight the lock of the steering wheels, all four wheels will always each follow a separate track and run smoothly around a common centre situated somewhere on the axial line of the front; wheels.

On depression of the left hand pedal the same proposition obtains in reverse direction. The intersection point X and the concentric tracks of the wheels are indicated in Fig. 2, it being assumed that the chair is turning to the left.

A modified cam construction is illustrated in Fig. 5. Therein, an auxiliary cam Be is secured to the underside of the cam 13, being arranged eccentrically of the stem H. A chain I5a is-secured at 152) to each auxiliary cam l3a, so that in this construction two chains are used.

When the right hand cam 13 is turning to the right, the chain I5 is pulled around on a curve of increasing circumference, pulling the other cam I3 so that the portion of chain l5 around it is travelling on a decreasing circumference. Therefore the second cam is turning at a faster rate than the first one, and the speed of the latter becomes progressively faster. As the first cam l3 turns to the right, its auxiliary cam l3a. turns with it and pays out the chain ifia on an increasing circumference, and as the second cam I3 is pulled around by the chain Hi, the second auxiliary cam l3a turns with it and winds in the chain lid on a decreasing circumference.

The eccentricity of the auxiliary cams l3a provide variations in the track which the auxiliary chain l5a is caused to travel, said variations being complementary to the chain movement around the main cams 13.

The principal object. of this construction is to prevent the chair wheels from toeing in and to maintain correct alignment as they pivot for turning.

In Figs. 3 and 4 a modified form of cam operating mechanism is illustrated, comprising a superstructure 30 supported on a shaft 3| by a rotatable sleeve 32. The shaft 3| is attached to an arm 33 offset from and fixedly secured to a rotatable rear stem H. The drag arm or cable 25 is pivotally attached at 34 to a skirt 35 on a carriage 38 which is adjustable as to position on the sleeve 32. Portion of the front edge of the superstructure 30 is provided with recesses 31, 33, and 39. The setting of the carriage 36 determines the location of the recesses, 31, 3B and 3S relatively to the stop 29 which in this case is fixed in the drag link 21. The sleeve 32 is provided with slots 32a and the position of the carriage 38 is adjustable by passing the set screw 322) into the appropriate slot in the sleeve 32. As illustrated in Fig. 4, the wheels 9 are in full lock and the carriage 36 has been positioned so that the recess 31 has been engaged by the stop 29.

The above construction enables the drag link 21 to swing on a lesser or greater are according to the amount of movement the user is capable of applying to the operating mechanism by his feet or hands.

In addition the steering may be made more sensitive to enable the chair to be turned quickly, or the steering may be made coarse, as desired, by making the appropriate adjustment; of the carriage 36.

I claim:

1. Improved passenger propelled wheel chair having front wheels mounted in fixed alignment, rear wheels each mounted on a stem adapted to rotate about a vertical axis, and steering means adapted to impart a differential movement to said rear wheels, so that the latter travel around a common turning point, said steering means including a cam fixed on each rotatable stem, means to connect said cams so that they rotate in the same direction at a different rate, and for each earn, an individual lever system connected to said cam and adapted to be controlled by the user, a flexible coupling having one end connected to said lever system, an articulated drag link pivotally secured to said cam and connected to the other end of said flexible coupling, and means to adjust the movement of said lever systerm.

2. Improved passenger propelled wheel chair having two rear wheels and steering means associated therewith, wherein the steering means associated with each rear wheel include a rotatable stem, a cam rigidly secured relatively to said stem, an articulated drag link pivotally connected to said cam and a connecting member extending forwardly from said drag link to actuating means, a peripheral track around the edge of each said cam and a flexible member connecting the said cams and arranged in said tracks whereby when one cam actuating means is operated, a forward pull is exerted on the associated connecting member and the corresponding cam is rotated, the said flexible member being wound on the actuated cam on a curve of increasing radius, and paying off the other cam on a curve of decreasing radius, so that a differential turning movement in the same direction is imparted to the said rear wheels.

3. Improved passenger propelled wheel chair according to claim 2, wherein a stop pin on each said cam is adapted to contact with the drag link associated therewith to provide a leverage to assist the actuating mechanism to turn the cam in the opposite direction.

4. Improved passenger propelled wheel chair according to claim 2 wherein each drag link is articulated and is pivotally connected to an adjustable sleeve carried on a shaft extending in offset relationship from the rotational centre of said cam, a member extending forwardly of said shaft, and a series of recesses in the front edge of said member, one or other of said recesses being adapted to engage a stop pin extending from the said articulated drag link, substantially as and for the purposes set forth.

5. Improved passenger propelled wheel chair having two front wheels of relatively large diameter mounted in fixed alignment, two rear :Wheels of relatively small diameter each carried by a rotatable stem, a cam fixed on each rotatable stem, a flexible member to connect the said cams so that they are capable of rotation in the same direction at a different rate, means to actuate each said cam comprising individual lever systems arranged to be controlled by the user, two flexible couplings, each having one end connected to one of said lever systems, respectively, an articulated drag link pivotally secured to each said cam, and to which the other end of the corresponding flexible coupling is connected, and a stop pin on each said cam adapted to contact with the articulated drag link attached thereto according to the direction in which the said cams are turned.

6. Improved passenger propelled wheel chair, having two front wheels of relatively large diameter mounted in fixed alignment, two rear wheels of relatively small diameter each carried by a rotatable stem, a main cam fixed on each rotatable stem, a flexible member connecting the said cams so that they are capable of rotation in the same direction at a different rate, an auxiliary cam secured below each said main cam, each said auxiliary cam being arranged eccentrically relatively to the rotatable stem with which it is associated, a peripheral track around each said auxiliary cam and a flexible coupling secured to the said auxiliary cams in the peripheral tracks thereof, a lever system adapted to actuate each said main cam and associated auxiliary cam according to the direction in which the wheel chair is to be turned, an articulated drag link pivotally secured to each said main cam, a stop pin on each said main cam adapted to contact with the said articulated drag link attached thereto according to the direction in which the said cams are turned, and a flexible coupling between each said lever system and each said drag link.

7. Improved passenger propelled wheel chair, having two front wheels mounted in fixed alignment, two rear wheels of relatively small diameter each carried by a rotatable stem, cams on said rotatable stems, respectively, connected by a flexible member, lever means to actuate each said cam, a flexible coupling connecting each said 16- ver means to its cam, a drag link pivotally seowed to each said cam, each said drag link being articulated and pivotally connected to an adjustable sleeve carried on a shaft extending in offset relationship from the rotational centre of each said cam, a member extending forwardly of said shaft, a series of recesses in the 'front edge of said member, and a stop pin extending from each said drag link, said stop pin being adapted to engage one or other of the said recesses according to the selected setting of the said adjustable sleeve.

8. Improved passenger propelled wheel chair having two front wheels mounted in fixed alignment, two rear wheels, and steering means for said rear wheels including 'for each rear Wheel a vertical stem rotatable about its own axis, two transmission cams rigidly secured to said stems, respectively, said transmission cams being provided with peripheral tracks on their horizontal edges, passenger controlled actuating means for alternatively rotating one of said transmission cams in one direction or the other transmission cam in the opposite direction, a, flexible member of definite length connecting said transmission cams and arranged in said tracks with its ends secured to said two transmission cams, respectively, the curvature of the tracks on said transmission cams being so plotted that, upon rotation of one of said transmission cams by said actuating means, said flexible member is wound on said actuated transmission cam on a curve of increasing radius and paid off the other transmission cam on a curve of decreasing radius thereby imparting to the rear wheels such differential turnin movement that upon any turning of the rear wheels from their parallel straight ahead position to their full lock position the point of intersection between the axial lines of the two rear wheels travels along the axial line of the front wheels from infinity to a point midway of the front Wheels, an auxiliary cam secured below each transmission cam, a peripheral track around each said auxiliary cam, and a flexible element secured to said auxiliary cams in the peripheral tracks thereof, whereby, as the flexible member connecting the transmission cams moves around a transmission cam on a curve of increasing radius, the associated auxiliary cam turns with it and pays out the flexible element connected thereto on a curve of increasing radius to prevent the rear wheels from toeing in and to maintain correct alignment for tracking as the rear wheels turn.

ALPHONSUS GERARD IGNATIUS MICHAEL KELLEY. 

